title: The signal transducers Stat1 and Stat3 and their novel target Jmjd3 drive the expression of inflammatory genes in microglia.
abstract: Most neurological diseases are associated with chronic inflammation initiated by the activation of microglia, which produce cytotoxic and inflammatory factors. Signal transducers and activators of transcription (STATs) are potent regulators of gene expression but contribution of particular STAT to inflammatory gene expression and STAT-dependent transcriptional networks underlying brain inflammation need to be identified. In the present study, we investigated the genomic distribution of Stat binding sites and the role of Stats in the gene expression in lipopolysaccharide (LPS)-activated primary microglial cultures. Integration of chromatin immunoprecipitation-promoter microarray data and transcriptome data revealed novel Stat-target genes including Jmjd3, Ccl5, Ezr, Ifih1, Irf7, Uba7, and Pim1. While knockdown of individual Stat had little effect on the expression of tested genes, knockdown of both Stat1 and Stat3 inhibited the expression of Jmjd3 and inflammatory genes. Transcriptional regulation of Jmjd3 by Stat1 and Stat3 is a novel mechanism crucial for launching inflammatory responses in microglia. The effects of Jmjd3 on inflammatory gene expression were independent of its H3K27me3 demethylase activity. Forced expression of constitutively activated Stat1 and Stat3 induced the expression of Jmjd3, inflammation-related genes, and the production of pro-inflammatory cytokines as potently as lipopolysacharide. Gene set enrichment and gene function analysis revealed categories linked to the inflammatory response in LPS and Stat1C + Stat3C groups. We defined upstream pathways that activate STATs in response to LPS and demonstrated contribution of Tlr4 and Il-6 and interferon-γ signaling. Our findings define novel direct transcriptional targets of Stat1 and Stat3 and highlight their contribution to inflammatory gene expression.
  
  
  CONCLUSIONS
  Combined analysis of genomic Stat occupancy and transcriptome revealed novel Stat target genes in LPS-induced microglia. Jmjd3 transcription factor is a novel transcriptional target of Stat1 and Stat3. Stat1 and Stat3 cooperate with Jmjd3 to induce the expression of pro-inflammatory genes. Constitutively active Stat1 and Stat3 fully mimic the LPS-induced upregulation of inflammatory genes and secretion of cytokines.
authors.affiliation: Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Przanowski
authors.forename: Michal
authors.initials: M
authors.lastname: Dabrowski
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Ellert-Miklaszewska
authors.forename: Michal
authors.initials: M
authors.lastname: Kloss
authors.forename: Jakub
authors.initials: J
authors.lastname: Mieczkowski
authors.forename: Beata
authors.initials: B
authors.lastname: Kaza
authors.forename: Anna
authors.initials: A
authors.lastname: Ronowicz
authors.forename: Feng
authors.initials: F
authors.lastname: Hu
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Piotrowski
authors.forename: Helmut
authors.initials: H
authors.lastname: Kettenmann
authors.forename: Jan
authors.initials: J
authors.lastname: Komorowski
authors.forename: Bozena
authors.initials: B
authors.lastname: Kaminska
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D016207:Cytokines / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D007249:Inflammation / Q000235:genetics*; D056484:Jumonji Domain-Containing Histone Demethylases / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008239:Lysine / Q000378:metabolism; D008745:Methylation / Q000187:drug effects; D017628:Microglia / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D050794:STAT1 Transcription Factor / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000378:metabolism*
chemical_list: D016207:Cytokines; D006657:Histones; D008070:Lipopolysaccharides; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D056484:Jumonji Domain-Containing Histone Demethylases; C000655037:Kdm6b protein, rat; C523761:Kdm6b protein, mouse; D008239:Lysine